In the construction field it is customary to install ventilation openings in walls to allow the passage of air and limit the accumulation of condensation. The opening, once formed, is generally filled by a slatted or otherwise weather-protected fitting, called herein a "ventilation louvre", or "louvre".
The function of a louvre is to permit the passage of air, while deflecting rain that might otherwise enter through the opening in the wall. Often louvres are installed on exterior walls that are faced with clapboard or siding. On occasion, they are installed in brick faced walls. In all such cases it is desirable, for aesthetic purposes, that the louvre should screen or cover the edges of the opening cut in the wall. The edges of the louvre should also be sealed against the exterior facing of the wall to prevent the entry of rain running down the exterior surface into the opening cut in the wall. This latter requirement is generally met by applying caulking between the outer border of the louvre, and the covering on the side of the building.
It has been customary in the past to install a louvre on the framing for a wall prior to the application of the final covering. To effect the attachment of prior art louvres to the framing, such louvres have been equipped with flanges that extend beyond the diameter of the body of the louvre. When brick or siding is then applied to the wall, and cut so as to abut the body of the louvre, the louvre essentially becomes "locked-in". The flanges prevent its removal without removing a portion of the brick or siding.
An alternate construction procedure entails completing the entire covering of the wall, in brick or siding, before installing the louvre. A hole is then cut for the installation of the louvre. In such a case it is not possible, without opening a hole of excessive width, to install a louvre that has outwardly extending flanges which attach the louvre to the interior framing. It is possible to attach the louvre to the exterior covering, and this has been done in the past. But it would be preferable to provide for a louvre that could be installed in an opening after a wall is covered, and still be attached to the interior studding or supports of the building.
As mentioned previously, it is desirable to seal the outer boundary of the louvre against the exterior wall surface to prevent the entry of water around its edges. A flat circular exterior ring or flange may be applied around the outside boundary of the body of the louvre to screen the edges of the wall covering and close-over gaps between that covering and the body of the louvre. When the wall surface is perfectly smooth the residual gaps between the flange and wall surface in such a case are small, and may easily be sealed with caulk. Thus on a non-textured or non-contoured exterior wall surface, the procedure for sealing the exterior of a louvre is relatively simple.
Where an exterior wall is textured or contoured, however, as in the case of clapboard, aluminum or plastic siding, or even brick-work where the bricking style leaves an uneven surface, considerable gaps and cracks may exist. These gaps may not so easily be filled with caulk if they are particularly large.
An improved means of ensuring an intimate fit between the outside of a louvre and adjacent textured or contoured wall surface would therefore be desirable. Further, it would be desirable to provide a louvre with an improved means by which it may be attached to the structural supports of a wall with such a contoured surface, after the exterior covering has been installed.
These and other benefits are accommodated by the invention which is hereafter described.